1. Field of the Invention
This invention relates to the preparation of cyclohexenyl and alkenyl aromatic compounds. In one aspect, the invention relates to the decarboxylation with concurrent dehydrogenation of cyclohexane and alkyl aromatic carboxylic acids while in another aspect, the invention relates to the use of certain copper and copper-molybdenum oxide compositions as decarboxylation catalysts. In yet another aspect, the invention relates to a novel process for preparing styrene.
2. Description of the Prior Art
Various processes are known for decarboxylating a carboxylic acid. For example, Fenton, U.S. Pat. No. 3,530,198, teaches a liquid-phase preparation of olefins from carboxylic acids by a process comprising contacting the acid with a complex catalyst comprising a Group VIII noble metal and a biphyllic ligand. Daumiller et al. U.S. Pat. No. 2,310,762, teach the vapor-phase preparation of aromatic vinyl compounds from carboxylic esters of aryl-substituted aliphatic alcohols. Other similar processes are known but do not include a concurrent dehydrogenation of the starting material. For example, Horeau et al., U.S. Pat. No. 3,080,419, teach a liquid-phase decarboxylation without concurrent dehydrogenation of various indene compounds and Pine, U.S. Pat. No. 3,476,803, teaches the decarboxylation of carboxylic acids to organic compounds having one less carbon atom than the starting material by contacting the acid with an active form of a crystalline zeolite having the structure of faujasite.
For various reasons none of the above processes are entirely satisfactory. Consequently, there exists an interest in developing new processes for preparing various olefinic compounds by decarboxylating corresponding paraffinic carboxylic acids.